P1371 Fault Code on 1996 Chevrolet Impala SS: Causes, Diagnosis, and Fixes

P1371 typically indicates that the Powertrain Control Module (PCM) is not receiving sufficient low-resolution pulses from the distributor's optical sensor. The most common cause is a faulty distributor, especially one with worn or corroded components. Unless there's a known PCM issue (which is rare), the problem usually lies in the distributor itself or its wiring connections.

I recently replaced my distributor. I'll need to verify proper installation and alignment to ensure it’s seated correctly. Thanks for the tip!

This code suggests that the PCM isn't receiving signals from the low-res optical sensor — essentially a high-precision camshaft position sensor. Possible causes include loose or damaged wiring, incorrect sensor alignment, transposed wires, or a disconnected harness. Always inspect the wiring harness leading to the PCM for breaks or corrosion. A scope can help verify sensor signal integrity during testing.

I checked all wiring connections and cleaned several corroded terminals. The P1371 code disappeared overnight, but later returned with a new code: P0171 (System Too Lean Bank 1). I suspect an exhaust leak on the driver's side — if it’s upstream of the oxygen sensor, it could contribute to lean conditions. However, my car failed to start one night and wouldn’t restart until after a full day. Now it shows codes P0102, P0372, and again P1371. It feels like the vehicle is acting up randomly — possibly due to electrical instability or environmental exposure. Could a failing PCM be involved?

A failing wiring harness or poor connection to the PCM could also trigger this code. The issue may not be with the sensor itself but rather signal integrity in the wiring.

I’ve been experiencing intermittent stalling — the car runs fine for a few minutes, then shuts off completely. After it dies, I can’t restart it until after a long wait. The P1371 code reappears consistently. Any additional diagnostics or troubleshooting steps?

A faulty crankshaft position sensor could mimic ignition-related codes and cause erratic behavior — worth checking if the engine fails to start or stalls suddenly.

An exhaust leak generally won’t cause lean conditions unless it’s located directly upstream of the oxygen sensor. Check for vacuum leaks, especially at hoses and intake fittings, as these can significantly affect air-fuel mixture readings.

I own a 1996 Chevrolet Caprice 9C1 and am experiencing identical symptoms: P1371, P0102, and P0372. The car sputters intermittently, sometimes dies on its own, and the electrical system becomes unstable. After replacing my distributor — which had severe corrosion on the rotor — most issues improved. However, it still randomly shuts off and throws P1371 when attempting to restart. I suspect wiring degradation or a failing sensor circuit. A full wiring inspection might be necessary, though it’s time-consuming.

I finally installed a new distributor. The car now runs smoothly with no electrical issues. Thanks to everyone for the helpful advice! The only remaining code is P0411 (Secondary Air Injection System Incorrect Flow). Does anyone know how to fix this?

For detailed technical reference, visit https://www.alldata.com — a trusted resource for vehicle-specific diagnostic codes and repair procedures.

The original post mentions that the user was also seeing P0335 and P0336 (Crankshaft and Camshaft Position Sensor) codes. These are related to timing and sensor accuracy, which may compound issues with P1371 when combined with distributor or sensor faults.